1. Field of the Invention
The invention relates to a method for treating lung disease, and more particularly, the invention relates to a method for treating the lungs by applying energy to the airways to reduce the ability of the airways to constrict or to reduce the resistance to airflow through the airways.
2. Brief Description of the Related Art
Asthma is a disease in which (1) bronchoconstriction, (2) excessive mucus production, and (3) inflammation and swelling of airways occur, causing widespread but variable airflow obstruction thereby making it difficult for the asthma sufferer to breath. Asthma is a chronic disorder, primarily characterized by persistent airway inflammation. However, asthma is further characterized by acute episodes of additional airway narrowing via constriction of hyperresponsive airway smooth muscle.
Asthma stimuli may be allergenic or non-allergenic. Examples of allergenic stimuli include pollen, pet dander, dust mites, bacterial or viral infection, mold, dust, or airborne pollutants; non-allergenic stimuli include exercise or exposure to cold, dry air.
In asthma, chronic inflammatory processes in the airway play a central role. Many cells and cellular elements are involved in the inflammatory process, particularly mast cells, eosinophils T lymphocytes, neutrophils, epithelial cells, and even airway smooth muscle itself. The reactions of these cells result in an associated increase in the existing sensitivity and hyperresponsiveness of the airway smooth muscle cells that line the airways to the particular stimuli involved.
The chronic nature of asthma can also lead to remodeling of the airway wall (i.e., structural changes such as thickening or edema) which can further affect the function of the airway wall and influence airway hyperresponsiveness. Other physiologic changes associated with asthma include excess mucus production, and if the asthma is severe, mucus plugging, as well as ongoing epithelial denudation and repair. Epithelial denudation exposes the underlying tissue to substances that would not normally come in contact with them, further reinforcing the cycle of cellular damage and inflammatory response.
In susceptible individuals, asthma symptoms include recurrent episodes of shortness of breath (dyspnea), wheezing, chest tightness, and cough. Currently, asthma is managed by a combination of stimulus avoidance and pharmacology.
Stimulus avoidance is accomplished via systematic identification and minimization of contact with each type of stimuli. It may, however, be impractical and not always helpful to avoid all potential stimuli.
Asthma is managed pharmacologically by: (1) long term control through use of anti-inflammatories and long-acting bronchodilators and (2) short term management of acute exacerbations through use of short-acting bronchodilators. Both approaches require repeated and regular use of the prescribed drugs. High doses of corticosteroid anti-inflammatory drugs can have serious side effects that require careful management. In addition, some patients are resistant to steroid treatment. Patient compliance with pharmacologic management and stimulus avoidance is often a barrier to successful asthma management.
Asthma is a serious disease with growing numbers of suffers. Current management techniques are neither completely successful nor free from side effects.
Accordingly, it would be desirable to provide an asthma treatment which improves airflow without the need for patient compliance.
In addition to the airways of the lungs, other body conduits such as the esophagus, ureter, urethra, and coronary arteries, are also subject to periodic spasms which cause hypertrophy and hyperplasia of the smooth muscle around these body conduits reducing the inner diameter of the conduits.
The present invention relates to a method for treating bodily conduits by transfer of energy to or from the conduit walls to prevent the conduit from being able to constrict, to enlarge the conduit, or to reduce resistance to flow through the conduit. The invention is particularly directed to the treatment of the airways in the lungs to reduce the effects of asthma and other lung disease.
The present invention provides methods to decrease airway responsiveness and airway resistance to flow which may augment or replace current management techniques.
In accordance with one aspect of the present invention, a method for treating conditions of the lungs by decreasing airway responsiveness includes transferring energy to or from an airway wall to alter the airway wall in such a manner that the responsiveness of the airway is reduced.
In accordance with an additional aspect of the present invention, the energy transferred to or from the airway wall alters the structure of the airway wall.
In accordance with a further aspect of the present invention, the energy transferred to or from the airway wall alters the function of the airway wall.
In accordance with another aspect of the present invention, a method for treating conditions of the lungs by decreasing airway resistance to airflow includes transferring energy to or from an airway wall to alter the airway wall in such a manner that a resistance to airflow of the airway is decreased.
The present invention provides advantages of a treatment for asthma or other constriction or spasm of a bodily conduit by application of energy. The treatment reduces the ability of the airway to contract, reduces plugging of the airway, and/or increases the inner airway diameter.